1. Field of the Invention
The present invention relates to an information processing apparatus and a duplex transmission method.
2. Description of the Related Art
In mobile terminals typified by a mobile telephone, a movable member is frequently used in a connection portion between a manipulation portion manipulated by a user and a display portion on which information is displayed. For example, a structure for opening and closing a foldable mobile telephone is a representative example of the movable member. In addition to a talking function and a mail function, a video image viewing function and an imaging function are incorporated in the recent mobile telephone. Therefore, the connection portion is demanded to be movable in a complicated way as usage of the user. For example, in cases where the video image viewing function is utilized, the user causes the display portion to face the user side while accommodating the manipulation portion unnecessary for the viewing. In cases where the mobile telephone is used as a normal telephone, in cases where the mobile telephone is used as a digital camera, or in cases where the mobile telephone is used as a television receiver, there is a demand for a structure in which the orientation and position of the display portion can easily be changed on each usage.
However, many signal lines and power lines are provided in the connection portion between the manipulation portion and the display portion. For example, tens lines are connected in parallel in the display portion (see FIG. 1). Therefore, when the movable member that can be moved in the complicated way is used as the connection portion, reliability of the lines is remarkably lowered. For this reason, a technique is shifted from a parallel transmission system to a serial transmission system (see FIG. 2) in order to decrease the number of lines of the connection portion. Obviously, for the similar reason, the technical shift is generated in not only the mobile telephone but also various electronic instruments in which complicated wiring is demanded. There is also another reason the serialization is advanced in order to reduce Electro Magnetic Interference (EMI).
In the serial transmission system, transmitted data is transmitted after coded by a predetermined system. Examples of the coding system include NRZ (Non Return to Zero) coding system, Manchester coding system, and AMI (Alternate Mark Inversion) coding system. For example, Japanese Patent Application Laid-Open No. 3-109843 discloses a technique of transmitting data by utilizing the AMI code that is of a typical example of a bipolar code. Japanese Patent Application Laid-Open No. 3-109843 also discloses a technique, in which a data clock is transmitted while expressed by an intermediate value of a signal level and the data clock is reproduced on the reception side based on the signal level.